I have the Still x64 version of LibO (188.8.131.52) installed on Mint 17.3 x64 KDE (and also at Windows).
I have problem with Themes. I can’t see any of them.
I’m going Tools → Options → (LibreOffice) Personalization → Own Theme → Select Theme, but here all lists (LibreOffice, Abstract, Color, Music, Nature) are empty.
They used to work, at previous versions.